app_main:=main.c
app_main+=hello.o
app_hello:=hello.c

main: $(app_main)
	gcc -o $@ $^
	./$@

hello.o: $(app_hello) hello.h
	gcc -c $(app_hello) -o hello.o

.PHONY: clean
clean:
	rm -f *.o
	rm -f main

